I don't usually post this kind of train photo here on the blog. I took this in Pennsylvania at the historic Rockville Bridge which is the largest stone masonry arch bridge in the world. I was photographing just the bridge but then got lucky when a train started across it as well. Norfolk Southern still uses this bridge and crosses it very slowly. I would guess to keep vibrations to a minimum so as not to cause damage. This image has a slight HDR effect added to it. I also cropped it to a bit panoramic view.